Sockets for prong socket electrical contacts and in their methods of manufacture

ABSTRACT

The socket comprises a portion cut out into contact strips by longitudinal slots and has, over at least a fraction of its length comprising the portion cut into strips, a cross section internally limited by a closed continuous curve and externally by a polygonal closed line. The longitudinal slots are closed at their longitudinal ends and pass through the vertices of the polygonal closed line. The strips are concave in axial direction. The socket ensures good electrical contact even after numerous insertions and extractions.

United States Patent Bonhomme 1 Feb. 8, 1972 [54] SOCKETS FOR PRONGSOCKET ELECTRICAL CONTACTS AND IN THEIR METHODS OF MANUFACTURE [72]Inventor: Francois Robert Bonhomme, Saint-Cloud,

France [73] Assignee: Connectronics Corporation, New York,

[221 Filed: July 2,1910

21 Appl.No.i 51,773

{30] Foreign Application Priority Data July 4, 1969 France ..6922890[52] US. Cl. ..339/217 S, 339/258 A [51] Int, Cl. ..H0lr9/12,I-I0lr11/22 [58] Edd oISearch ..339/217, 256, 258, 252, 176; 29/129,130 A;287/126; 24/115 H, 155 R, 155 D,

155 BB, 201 S, 158, 230 R, 230 SL, 257

[56] References Cited UNITED STATES eATsN'rs 3,396,364 8/1968 Bonhomme.Q .339/217 FOREIGN PATENTS OR APPLICATIONS 1,479,600 3/1967 France..339/ 258 927,342 5/ 1 955 Germany 339/256 993,316 5/1965 Great Britain....339/256 1 14,988 8/1925 Switzerland ..339/25 8 A PrimaryExaminerMarvin A. Champion Assistant Examiner-Robert A. HaferAttorney-Waters, Roditi, Schwartz & Nissen [57] ABSTRACT The socketcomprises a portion cut out into contact strips by longitudinal slotsand has, over at least a fraction of its length comprising the portioncut into strips, a cross section internally limited by a closedcontinuous curve and externally by a polygonal closed line. Thelongitudinal slots are closed at their longitudinal ends and passthrough the vertices of the polygonal closed line. The strips areconcave in axial direction. The socket ensures good electrical contacteven after numerous insertions and extractions.

10 Claims, 10 Drawing figures PMENFEBFm 8 m2 SHEET 1 UF 4 PAIENTEBFEB81912 3.641.483

SHEET 3 (IF 4 SOCKETS FOR PRONG SOCKET ELECTRICAL CONTACTS AND IN THEIRMETHODS OF MANUFACTURE v The invention relates to sockets, for prong andsocket electrical contacts, of the type which comprises a portion cutout into contact strips by longitudinal slots and which, over at least afraction of their length comprising the above-said portion cut out intostrips, have a transverse section limited internally by a continuousclosed curve and, externally, by a polygonal closed line inscribed in acurve parallel to the first.

Sockets of this type are already known and give satisfactory results.However, the quality of the electrical contact ensured by such sockets,especially afier numerous insertions and extractions, can be furtherimproved.

It is a particular object of the invention, to render the sockets suchthat they ensure good electrical contact, even after numerous insertionsand extractions.

According to the invention, a prong and socket electrical contact socketof the type concerned is characterized by the fact that, on one hand,the longitudinal slots are closed at their longitudinal ends and passthrough the vertices of the polygonal closed line and that, on the otherhand, the strips of the above-said portion are concave in axialdirection and are adapted to be deformed on uniting the socket with aprong.

Advantageously, when the socket is intended to be mounted in a housingprovided in an insulating support, one of the strips at least is cut outby a transversal slot extending between two neighboring longitudinalslots, into two tongues arranged head to tail with respect to oneanother and the tongues fonned by the one or more transversely cut outstrips separate inwardly so as to project by their free ends on theouter surface of the socket and to be able to cooperate with a lockingboss provided in the above-said housing.

The invention also relates to a method of manufacturing a socket such asdefined above.

This method is characterized by the fact that it commences with aprismatic solid body of polygonal cross section, that grooves arefashioned over a fraction of the length of the crests of the outersurface, that a longitudinal cavity is pierced in the body whosetransverse section has dimensions such that the above-said grooves openinto the cavity and constitute the slots dividing the intermediateportion of the socket into strips and that the intermediate portion ofthe body is then subjected to a permanent mechanical deformation adaptedto give the strips their axial concavity.

The invention consists, apart from the features mentioned above, incertain other features which are preferably used at the same time andwhich will be more explicitly considered below with regard to preferredembodiments of the invention which will now be described in moredetailed manner with reference to the accompanying drawings but whichare in no way limiting.

FIG. 1 of the drawings shows, in perspective, a socket constructedaccording to the invention and the end of a prong corresponding to thesocket.

FIG. 2 shows partly in cross section at the level of its intermediateportion, and partly in end view, the embodiment of the socket of FIG. 1.

FIG. 3 is a partial section along the line III-III of the FIG. 2.

FIG. 4 shows, in perspective, another type of socket constructedaccording to the invention.

FIGS. 5 and 6 show in cross section a socket at difi'erent stages ofmanufacture.

FIG. 7 shows, in perspective, another embodiment of a socket accordingto the invention which is a variation of that shown in FIG. 1.

FIG. 8 shows the embodiment of FIG. 7 mounted in an insulating support.

FIG. 9 shows one of the phases of the method of manufacturing theembodiment of the FIG. 7, in the case of manual execution.

Lastly, FIG. 10 shows the same phase of the method of manufacture asFIG. 9, but in the case of execution on an automatic machine.

Referring to FIG. 1, there can be seen a socket l of rectilinear tubularshape, having a longitudinal cavity 2 intended to receive a cylindricalprong 3.

The socket 1 includes a'concave intermediate portion 4 (in the directionparallel to the axis of insertion) whose internal cross section, inresting position, has dimensions and a surface less than those of thecross section of the prong 3. At one end, the socket 1 can include acylindrical tail T for connecting to an electrical conductor.

When the prong 3 is introduced into the cavity 2, the intermediateportion 4 must then be deformed to enable the prong to pass. By reasonof this deformation and, in consequence of the elasticity of thisintermediate portion of the socket l, the inner surface 5 of the saidintermediate portion constitutes a contact surface which will exertpressure on the prong 3, which contributes to establishing goodelectrical contact between the said prong and socket.

The socket 1 has, at least over a fraction 6 of its length comprisingthe said intermediate portion 4, a cross section limited internally by aclosed continuous curve 7 corresponding to the section of the contactsurface 5 or of its extension 8 and, externally, by a polygonal closedline 9 inscribed in a curve I0 parallel to the first curve 7.

The intermediate portion 4 is cut out into strips 11 by longitudinalslits l2 closed at their ends 13 and passing through the apices 14 ofthe polygonal closed line 9.

The continuous curve 7 is generally constituted by a circumference andforms an inner geometrical limit of the transverse section of thesocket. As can be seen in FIG. 2, at the right of the slits 12, thecurve 7, shown in mixed line and displaced radially towards the insideto facilitate the reading of the drawing, is extended in imaginarymanner while in reality the inner contour of the section is formed by aseries of arcs of the curve 7 separated from one another by the slits12.

The polygonal closed line 9 is, preferably, constituted by a hexagonalcontour 15 which can be regular when the curve 7 is a circumferencesince the curve 10, parallel to the curve 7, is then constituted by aconcentric circumference.

The contour 15 being hexagonal, the slits 12 are six in number,corresponding to the number of apices of the contour 15. These slitstraverse the wall of the intermediate portion 4, which gives a goodflexibility to the strips 11. The ratio of the length of the slits 12 tothe diameter of the circumference constituting the curve 7 can varywithin fairly wide limits, of the order of 2 to 12.

The elasticity of the intermediate portion 4 of such a socket is verygood, even if the socket l is formed of brass, copper or aluminum, ofwhich materials the coeficient of elasticity is low.

Thickness of the wall of the socket 1, between two slots 12 or betweentwo apices 14 of the polygonal line 9 (see FIG. 2) diminishes, pasesthrough a minimum, then increases to resume its value, which enables theportion 4, on extraction of a prong, to resume with precision itsresting position after the deformation caused by the introduction of thesaid prong.

In addition, due to the fact that the slots 12 are closed at their twolongitudinal ends 13, the strips 11 rejoin at the ends of the said slots12. The strips 11 are hence, in a way, held, at each of their ends, by abelt which is opposed to the outward separation of the said strips 11 onthe introduction of the prong 3 into the cavity 2. As a result there isvery good electrical contact between the prong and the socket and thequalityv of this contact is maintained after numerous insertions andextractions.

In another embodiment shown in FIG. 4, the polygonal outer contour,denoted here by 9a, can be constituted by an equilateral triangle 16,the slots being three in number and passing through the vertices of thetriangle. The other elements similar to those of FIGS. 1 to 3 bear thesame reference numerals, followed, in FIG. 4, by the letter a.

To produce such a socket 1, the method may be as follows, purely by wayof nonlinriting example.

Initially a solid body is taken, of prismatic outer surface, preferablyof regular hexagonal crom section.

The slots 12 are machined by a milling along the fraction of the lengthof the crests of the surface of the body and to a certaindepthh,sothatthe crosssectionofthe body, inthe portion where the slots 12 havebeen milled, is as shown in FIG. 5, at this first stage of themanufacture of the socket l. The slots 12 are closed at theirlongitudinal ends.

Then there is pierced'in the axis of the body a longitudinal cylindricalhole of radius R (FIG. 6) such that the sum of thisradiusRandthedepthhoftheslots l2isgreaterthanthedistancefromthecrestsoftheprismaticsolidtotheaxisof this solid. Underthese conditions, the slots 12 will open into thehole whose contour isshown in mixed line in FIG. 5. This precaution of engaging the tongues21, 22 in the corresponding grooves 27. The socket 1b is driven into thehousing 25 so that, along the orientation of the socket and along theend of the housing 25 through which the said socket has been introduced,the tongues 21 or 22 arrive in contact with the bosses 28.

For example, if the tail T of the socket lb has been introduced firstthrough the upper end (for FIG. 8) of the how ing 25, the driving in ofthe socket lb into the said housing is effected in the direction of thearrow F in this case, it is the tongues 22 which will arrive first incontact with the bosses 28.

' If an inserting force continues to be exerted on the socket lb,

operation of piercing enables thus to be eliminated the burrs I causedby the milling ofthe slots 12.

The cross section in the portion comprising the slots, at this stage ofmanufacture thesocket 1, is shown in FIG. 6,'by the contour in mixedline. The width ofthe slots 12 is then equal to L. v

Lastly, the portion comprising the slots is mechanically deformed inpermanent manner by a constricting operation, so as to obtain theportion 4 which has a concavity in the longitudinal direction. Thestrips 11 are displaced, in the course of this deformation, radiallyinwardly, from the position in line of FIG. 6 to the position incontinuous line of the sameFIG.Asaresultthereisareductionintheradiusofthe hole and, at the same time, areduction of the width of the slots 12 which become equal to l, I beingless than L.

In FIGS. 7 to 10, there is shown another embodiment 1 which is avariation lb of the socket l of FIG. 1. The elements of FIGS. 7 to 10identical with elements already encountered are denoted by the samereference figures followed by the letterband will notbedescribed again.

One of the strips llb at least is cut out by a transverse slot extendingbetween two neighboring longitudinal slots 12b so that two tongues 21,22, arranged head to tail with respect to one another, are formed fromthe strip 11b which has bee cut transversely.

The tongues 21, 22 separate outwardly so as to project by their ends orfree transverse edges 23, 24, over the outer surface of the socket lb.The said tongues have a rectangular contour of which three sides arefree, the fourth side being located at the junction of the tongue withthe outer surface of the socket.

, Preferably, when the polygonal line 9b is a regular polygon with aneven number of equal sides at least four in number, and especially inthe case of a hexagon, two diametrically opposite strips llb are eachcut into two tongues 21, 22 by a transverse slit 20, as shown in thedrawings.

In general, the slit 20 is arranged substantially midway along thelongitudinal slots 12b.

By referring to FIG. 8, it is seen that the socket lb is intended to bemounted in a housing 25 provided in a insulating support 26. The housing25 traverses the said support from one side to the other and opens on totwo opposite surfaces of this latter. The said housing 25 is limited bya prismatic surface whose cross section is slightly greater than thesection of the socket lb, the contour of the said cross section beingparallel to that of a transverse section of the socket lb.

One or several longitudinal grooves 27 arranged to receive the one ormore transversely cut strips 1 lb, are provided in the walls of thesupport 26 which bond the housing 25. The width of these strips isslightly greater than that of the tongues 21, 22. Midway along eachgroup 27, a boss 28 is provided. These bosses 28 are adapted tocooperate with the tongues 21, 22 on the introduction of the socket lbinto the housing 25, so as to ensure locking of the socket in the saidsupport. The grooves 27 open at each end of the housing 25.

The mounting of the socket lb in the support 26 is effected in thefollowing manner. The socket lb is introduced into the housing 25,through any end of the latter, by taking the the bosses 28 will causethe withdrawal of the tongues 22, which permits the socket 1b tocontinue to penetrate into the housing 25. As soon as the free edges 24of the tongues 22 have cleared the bosses 28, the said tongues 22, byreason of their elasticity, are raised and resume the position that theyhad before coming into contact with the bosses 28. The dimension of theboxes 28 along the direction of the arrow F, is equal to the width ofthe transverse slot 20, i.e., to the distance, along the direction F, ofthe free edges 23 and 24 of the tongues 21, 22. Thus, at the instantwhen the tongues 22 areraised,afierclearingthebosses28,thefreeedges23ofthe tongues 21 come intocontact with the surface of the said bosses opposite to that which issituated facing the free edges 24 of the tongues 22.

The cooperation of the tongues 21, 22 and the bosses 28 ensure on onehand, the positioning of the socket lb in the housing 25, along the axisof the latter, and, on the other hand, the locking of the socket in thesupport.

In FIG. 8, the surfaces of the bosses 28 which come into contact withthe free edges 23, 24 of the tongues, are substantially right angles tothe axis of the housing 25. In a variation of the embodiment, thesesurfaces could be inclined on the said axis so that the cross section ofthe bosses 28, instead of being rectangular as in FIG. -8, would betrapezoid, the small base being turned towards the axis of the housing25 and being less than the width of the slot 20, while the large base ofthe section of the boss furthest spaced from the axis of the housing,would have a dimension greater than the width of the slot 20.

It is obvious that instead of introducing the socket lb through theupper end of the housing 25, it could be introduced through the lowerend of the said housing along the arrow F the tongues 21 then comingfirst into contact with the bosses 28 and being withdrawn under theaction ofthese latter to be raised again after their clearance.

To extract the socket lb from its support 26, it suffices, for example,by means of a tool with two arms, in the case considered, arranged to beintroducable respectively into the two grooves 27, to withdraw thetongues 22 and to exert on the socket 1b a force in the direction of thearrow F, to extract the socket. Naturally, the tongues 21 could havebeen withdrawn by means of the above-said tool and a force exerted onthe socket lb in the direction of the arrow F, to extract the saidsocket through the lower end of the housing 25.

To produce a socket 1b such as that previously described, the procedureis advantageously as follows.

As previously described, there is first taken a solid prismatic bodywith a polygonal cross section. Groves are machined over a fraction ofthe length of the crests of the outer surface, the said grooves beingclosed at their ends. The longitudinal cavity 2b is then bored into thebody, the depth of the grooves and the dimensions of the cavity beingsuch that the abovesaid grooves open into the cavity and constitute theslots 12b which divide the intermediate portion 4b of the socket 1b intostrips 1 1b.

This being the case, there is effected on at least one of the stripsllb, and preferably on two diametrically opposite strips, in the case ofFIGS. 3 and 4, a transverse slit 20 separating each strip llb into twotongues 21, 22. Through this transverse slit 20 there is introduced atool 28 (FIG. 9).

This tool 28 includes, on one hand, a head 29 in the shape of an anvilprovided with two flat surfaces 29a, 29b inclined in sauna n-rnropposite directions, so as to form an obtuse angle, whose apex projectsoutwardly and, on the other hand, a handle 30. The

width 1 of the head-29 is lem than the width of the slot 20, while thelength h of the head 29 is less than the large dimension of the slot 20.

To introduce the tool 28 through the slot 20, it suflices to orient thelarge dimension of the head or anvil 29, i.e., its length h, along thedirection of the large dimension of the slot 20 and to displace the saidtool 28 along a transverse direction C towards the inside of the socketlb, by making the head 29 pan; between the free edges 23, 24 of thetongues 21, 22.

When the anvil 29 is in the cavity 2b, the said anvil is made, by actingon the handle 30, to undergo a rotation of about 90 and the said anvilisbrought into contact with the tongues 21, 22, which are again inextension of one another, the large dimension h of said anvil 29 beingthen oriented in the direction of the axis of the socket lb. There isthen exerted on the tongues 21, 22, by means of the anvil 29, a forcesufiicient to cause a permanent outward deformation of the said tongues21, 22. The tool is disengaged by repeating in reverse direction theoperations which had been necessary for the introduction of the latterinto the cavity 2b. This operation of deformation of the tongues iseffected for all the strips 11b which have been transversely cut. In thecase of FIG. 9, the anvil 29 is introduced into the cavity 2b throughthe slot 20 from the right to deform the tongues 21, 22 on the left andthrough the slot 20 on the left to deform the tongues 21, 22 on theright.

In a variation of the embodiment, to simplify operations, especially inthe case of automatic machines, and to efiect the deformations ofdiametrically opposite tongues with a single introduction of the toolinto the cavity 2b, there is given, as shown in FIG. 10, to the sectionof the anvil 29c through a plane right angles to the direction of thesmall dimension of this anvil, the shape of a losange. In this way, thedeformation of the tongues 21, 22 located on the left of FIG. will beobtained by a tlu'ust towards the left of the anvil 290 against thetongues, while the deformation of the tongues 21, 22 located on theright of FIG. 10, will be obtained by a traction exerted on the tool 280whose anvil 29c draws the tongues towards the right.

In the preceding explanations regarding the operations of deforming thetongues 21, 22, it has been implicitly assumed that the socket lb washeld by a device not shown.

Finally, the strips llb not cut transversely, are made to undergo apermanent mechanical deformation, so that the above-said intermediateportion 4b of the socket lb, becomes concave in axial direction.

The deformation of the strips 11b not being effected until after thedeformation of the tongues 21, 22, this explains why in FIGS 9 and 10,where the wcket 1b is shown at the moment of deformation of the saidtongues, the slots 12b have a rectangular shape, the strips 11b not yetbeing deformed.

As a result of which and whatever the embodiment adopted, there isobtained a socket adapted to ensure good electrical contact, even afternumerous insertions and extractions.

In fact, as explained in detail previously, due to the fact that theslots 12, [2a, 12b are closed at their ends, the strips 11 are supportedby belts which are opposed to the separation of the said strips 11, 11a,11b towards the outside of the socket. Due to the fact that the slots12, 12a, 12b pass through the apices of the polygonal lines 14, 14a,14b, the said strips have a transverse section such that they can berendered concave in axial direction.

In addition, the embodiment of FIG. 7 enables a socket to be obtainedwhose mounting and locking in an insulating support are simple andrapid.

As goes without saying and as emerges already besides from the precedingdescription, the invention is in no way limited to those of its methodsof application, nor to those of its methods of production of its variousparts, which have been more particularly indicated; it embraces on thecontrary all variations,

especially that in which the pol gonal contour 9, 9a, 9b would bedifferent from those descn previously and constituted for example by asquare or a rectangle.

What we claim is:

1. Socket for a prong and socket electrical contact, comprising aportion cut out into contact strips by longitudinal slots and having,over at least a fraction of its length comprising said portion, atransverse section limited internally by a closed continuous curve and,externally, by a polygonal closed line inscribed in a curve parallel tothe first, wherein the longitudinal slots are closed at theirlongitudinal ends and pass through the vertices of the polygonal closedline and the strips of said portion are concave in an axial directionand are adapted to be deformed on the connection of the socket and aprong.

2. Socket according to claim 1, arranged for mounting in a housingprovided in an insulating support, wherein at least one of said stripsis cut by a transverse slot extending between two neighboringlongitudinal slots into two tongues arranged head to tail with respectto one another and the tongues formed by the one or more transverselycut out strips separate outwardly so as to project by their free ends onthe outer surface of the socket and to be cooperable with a locking bossprovided in said housing.

3. Socket according to claim 1, wherein the closed continuous curve isconstituted by a circumference.

4. Socket according to claim 3, wherein the polygonal closed line is aregular polygon with the same center as the circumference, including aneven number of equal sides at least four in number.

5. Socket according to claim 4, wherein the regular polygon is ahexagon.

6. Socket according to claim 1, wherein the polygonal closed line isconstituted by the contour of an equilateral triangle.

7. Socket according to claim 2, including two diametrically oppositestrips, each cut into two tongues by a said transverse slot.

8. Socket according to claim 2, wherein the transverse slot is arrangedsubstantially midway along the longitudinal slot.

9. Method of manufacturing a socket for an electrical contact accordingto claim 1, comprising starting with a solid prismatic body of polygonalcross section, machining grooves over a fraction of the length of thecrests of the'outer surface, piercing a longitudinal cavity in the bodywhose cross section has dimensions such that said grooves open into thecavity and constitute slots dividing the intermediate portion of thesocket into strips and then subjecting the intermediate portion of thebody to permanent mechanical deformation adapted to give the stripstheir axial concavity.

10. Method according to claim 9 for manufacturing a socket, whereinbefore subjecting the intermediate portion of the body to said permanentmechanical deformation, one or several strips are provided with atransverse slot extending between two neighboring longitudinal slots, atool in the form of an anvil is introduced, the large dimension of theanvil being oriented along the direction of the transverse slot, saidanvil is subjected, inside the socket, to a rotation of about thetongues formed by the transversely cut out strip are brought intocontact with said anvil, whose large dimension is then oriented at rightangles to the large dimension of the transverse slot, a force sufficientto cause permanent deformation of said tongues outwardly is applied, andthe tool is disengaged.

1. Socket for a prong and socket electrical contact, comprising aportion cut out into contact strips by longitudinal slots and having,over at least a fraction of its length comprising said portion, atransverse section limited internally by a closed continuous curve and,externally, by a polygonal closed line inscribed in a curve parallel tothe first, wherein the longitudinal slots are closed at theirlongitudinal ends and pass through the vertices of the polygonal closedline and the strips of said portion are concave in an axial directionand are adapted to be deformed on the connection of the socket and aprong.
 2. Socket according to claim 1, arranged for mounting in ahousing provided in an insulating support, wherein at least one of saidstrips is cut by a transverse slot extending between two neighboringlongitudinal slots into two tongues arranged head to tail with respectto one another and the tongues formed by the one or more transverselycut out strips separate outwardly so as to project by their free ends onthe outer surface of the socket and to be cooperable with a locking bossprovided in said housing.
 3. Socket according to claim 1, wherein theclosed continuous curve is constituted by a circumference.
 4. Socketaccording to claim 3, wherein the polygonal closed line is a regularpolygon with the same center as tHe circumference, including an evennumber of equal sides at least four in number.
 5. Socket according toclaim 4, wherein the regular polygon is a hexagon.
 6. Socket accordingto claim 1, wherein the polygonal closed line is constituted by thecontour of an equilateral triangle.
 7. Socket according to claim 2,including two diametrically opposite strips, each cut into two tonguesby a said transverse slot.
 8. Socket according to claim 2, wherein thetransverse slot is arranged substantially midway along the longitudinalslot.
 9. Method of manufacturing a socket for an electrical contactaccording to claim 1, comprising starting with a solid prismatic body ofpolygonal cross section, machining grooves over a fraction of the lengthof the crests of the outer surface, piercing a longitudinal cavity inthe body whose cross section has dimensions such that said grooves openinto the cavity and constitute slots dividing the intermediate portionof the socket into strips and then subjecting the intermediate portionof the body to permanent mechanical deformation adapted to give thestrips their axial concavity.
 10. Method according to claim 9 formanufacturing a socket, wherein before subjecting the intermediateportion of the body to said permanent mechanical deformation, one orseveral strips are provided with a transverse slot extending between twoneighboring longitudinal slots, a tool in the form of an anvil isintroduced, the large dimension of the anvil being oriented along thedirection of the transverse slot, said anvil is subjected, inside thesocket, to a rotation of about 90*, the tongues formed by thetransversely cut out strip are brought into contact with said anvil,whose large dimension is then oriented at right angles to the largedimension of the transverse slot, a force sufficient to cause permanentdeformation of said tongues outwardly is applied, and the tool isdisengaged.